Nanotubes (NT) are considered as promising nano-reinforcement fillers in cement-based materials. The main challenge towards achieving a significant enhancement in cement properties is an effective dispersion of the agglomerated NT. In the talk I will demonstrate how efficient NT (carbon or WS2) dispersion in cement results in substantial flexural and compressive strength enhancements at NT concentration below 0.15 wt%. The reinforcement by WS2 NTs (see figure) remains significant after a variety of curing processes, suggesting a genuine nanoscale reinforcing effect. Finally, by employing a comprehensive fractography we show that the WS2 NTs inhibit crack propagation by bridging with a pullout failure mechanism.
SEM image of WS2 NT-based cement composite showing a WS2NT covered by a layer of Calcium-Silicate-Hydrate (C-S-H) phase.
